This report covers active volcanoes recorded from June 6 – June 11, 2012 based on Smithsonian/USGS criteria. New unrest has been noticed around 4 volcanoes, ongoing activity was reported for 12 volcanoes.
14.473°N, 90.880°W; summit elev. 3763 m
INSIVUMEH reported that on 6 June lahars descended Fuego's El Jute (SE), Las Lajas (SE), Ceniza (SSW), Santa Teresa (S), and Taniluyá (SW) drainages, and destroyed roads in Yepocapa (8 km WNW). During 6-7 June explosions produced ash plumes that rose 200-500 m above the crater and drifted N, and 12 km S and SW. Lavaflows on the SE flank were about 800-900 m long in the Las Lajas drainage, 600 m long in the El Jute drainage, and 250 m long on the SW flank, and produced blocks that rolled and reached vegetated areas. The explosions were accompanied by rumbling sounds and shock waves that were detected in areas 10 km away, including Panimaché and Morelia (~8 km SW).
During 10-11 June an ash plume rose 1.5 km above the crater and drifted 15 km W and NW. Ashfall was reported in Panimaché I and II, Sangre de Cristo (8 km WSW), Yepocápa, and other villages nearby. Lava flows traveled 1.6 km down Taniluyá drainage, 1 km down the Ceniza drainage, and 1.5 km down Las Lajas. Pyroclastic flows descended Las Lajas. During 11-12 June explosions generated ash plumes that rose 300 m above the crater and drifted W. Lava flows traveled 300 m down the Taniluyá drainage. Incandescence rose 100 m.
Geologic summary: Volcán Fuego, one of Central America's most active volcanoes, is one of three largestratovolcanoes overlooking Guatemala's former capital, Antigua. The scarp of an older edifice, Meseta, lies between 3,763-m-high Fuego and its twin volcano to the N, Acatenango. Construction of Meseta volcano continued until the late Pleistocene or early Holocene, after which growth of the modern Fuego volcano continued the southward migration of volcanism that began at Acatenango. Frequent vigorous historical eruptions have been recorded at Fuego since the onset of the Spanish era in 1524, and have produced major ashfalls, along with occasional pyroclastic flows and lava flows. The last major explosive eruption from Fuego took place in 1974, producing spectacular pyroclastic flows visible from Antigua.
1.22°N, 77.37°W; summit elev. 4276 m
On 5 June INGEOMINAS reported that seismicity at Galeras increased since the previous week and indicated continuing ash and gas emissions. Ash originated from an area N and W of the cone within the main crater and was emitted in a pulsating manner. Ash was deposited on the NW flanks. Ash emissions were especially frequent on 2 and 5 June, with plumes rising 1 km above the crater. The Alert Level remained at III (Yellow; "changes in the behavior of volcanic activity").
Geologic summary: Galeras, a stratovolcano with a large breached caldera located immediately W of the city of Pasto, is one of Colombia's most frequently active volcanoes. The dominantly andesitic Galeras volcanic complex has been active for more than 1 million years, and two major caldera collapse eruptions took place during the late Pleistocene. Longterm extensive hydrothermal alteration has affected the volcano. This has contributed to large-scale edifice collapse that has occurred on at least three occasions, producing debris avalanches that swept to the W and left a large horseshoe-shaped caldera inside which the modern cone has been constructed. Major explosive eruptions since the mid Holocene have produced widespread tephra deposits and pyroclastic flows that swept all but the southern flanks. A central cone slightly lower than the caldera rim has been the site of numerous small-to-moderate historical eruptions since the time of the Spanish conquistadors.
NEVADO DEL RUIZ, Colombia
4.895°N, 75.322°W; summit elev. 5321 m
According to INGEOMINAS, the Observatorio Vulcanológico and Sismológico de Manizales reported that a satellite image of Nevado del Ruiz acquired on 6 June showed an ash plume rising from the crater and drifting NW, and ash deposits on the N, NW, W and SW flanks. Based on analysis of satellite imagery and information from INGEOMINAS, the Washington VAAC reported that gas plumes possibly containing some ash drifted 75-110 km W, WNW, and N during 7 and 9-10 June. Ash plumes drifted almost 30 km SE on 8 June. INGEOMINAS reported that on 11 June seismic signals indicated continuing ash emissions. The Alert Level remained at II (Orange; "eruption likely within days or weeks").
Geologic summary: Nevado del Ruiz is a broad, glacier-covered volcano in central Colombia that covers >200 sq km. Three major edifices, composed of andesitic and dacitic lavas and andesitic pyroclastics, have been constructed since the beginning of the Pleistocene. The modern cone consists of a broad cluster of lava domes built within the summit caldera of an older Ruiz volcano. The 1-km-wide, 240-m-deep Arenas crater occupies the summit. Steep headwalls of massive landslides cut the flanks of Nevado del Ruiz. Melting of its summit icecap during historical eruptions, which date back to the 16th century, has resulted in devastating lahars, including one in 1985 that was South America's deadliest eruption.
POAS, Costa Rica
10.20°N, 84.233°W; summit elev. 2708 m
OVSICORI-UNA reported that phreatic eruptions at Poás occurred on 6, 15, 20 and 26 May. The eruption on 15 May was preceded by about 6 hours of very-low amplitude harmonic tremor. Administrators of the Poás Volcano National Park witnessed the eruption and reported that sediment, water, rock fragments, and plumes were ejected 500 m above the lake surface. The level of the lake dropped ~0.9 m between 8 and 29 May.
Geologic summary: The broad, well-vegetated edifice of Poás, one of the most active volcanoes of Costa Rica, contains three craters along a N-S line. The frequently visited multi-hued summit crater lakes of the basaltic-to-dacitic volcano, which is one of Costa Rica's most prominent natural landmarks, are easily accessible by vehicle from the nearby capital city of San José. A N-S-trending fissure cutting the 2,708-m-high complex stratovolcanoextends to the lower northern flank, where it has produced the Congo stratovolcano and several lake-filled maars. The southernmost of the two summit crater lakes, Botos, is cold and clear and last erupted about 7,500 years ago. The more prominent geothermally heated northern lake, Laguna Caliente, is one of the world's most acidic natural lakes, with a pH of near zero. It has been the site of frequent phreatic and phreatomagmatic eruptions since the firsthistorical eruption was reported in 1828. Poás eruptions often include geyser-like ejection of crater-lake water.
6.140°S, 155.195°E; summit elev. 1750 m
Based on analyses of satellite imagery, the Darwin VAAC reported that on 10 June ash plumes from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 45-130 km SW.
Geologic summary: Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. Bagana is a massive symmetrical lava cone largely constructed by an accumulation of viscous andesitic lava flows. The entire lava cone could have been constructed in about 300 years at its present rate of lava production. Eruptive activity at Bagana is characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50-m-thick with prominent levees that descend the volcano's flanks on all sides.
BATU TARA ,Komba Island (Indonesia)
7.792°S, 123.579°E; summit elev. 748 m
Based on analyses of satellite imagery, the Darwin VAAC reported that during 4-5 and 9-12 June ash plumes from Batu Tara rose to altitudes of 1.8-3 km (6,000-10,000 ft) a.s.l. and drifted 37-93 km NW and W.
Geologic summary: The small isolated island of Batu Tara in the Flores Sea about 50 km north of Lembata (formerly Lomblen) Island contains a scarp on the eastern side similar to the Sciara del Fuoco of Italy's Stromboli volcano. Vegetation covers the flanks of Batu Tara to within 50 m of the 748-m-high summit. Batu Tara lies north of the main volcanic arc and is noted for its potassic leucite-bearing basanitic and tephritic rocks. The first historical eruption from Batu Tara, during 1847-52, produced explosions and a lava flow.
CLEVELAND, Chuginadak Island
52.825°N, 169.944°W; summit elev. 1730 m
AVO reported that during 5-6 June elevated surface temperatures at Cleveland's summit were detected in satellite imagery. A low-level plume that rose to an altitude of 3.5 km (11,500 ft) a.s.l. was observed by a web camera on 6 June. A strong sulfur odor was reported by observers in Nikolski (75 km E). Clouds prevented views of the volcano on 7 June. Minor deposits of ash near the summit crater were observed in satellite images during 9-10 June and elevated surface temperatures were detected during 11-12 June. The Volcano Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.
Geologic summary: Symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited dumbbell-shaped Chuginadak Island in the east-central Aleutians. The 1,730-m-high stratovolcano is the highest of the Islands of Four Mountains group and is one of the most active in the Aleutians. Numerous large lava flows descend its flanks. It is possible that some 18th to 19th century eruptions attributed to Carlisle (a volcano located across the Carlisle Pass Strait to the NW) should be ascribed to Cleveland. In 1944 Cleveland produced the only known fatality from an Aleutian eruption. Recent eruptions from Mt. Cleveland have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks.
KARYMSKY, Eastern Kamchatka (Russia)
54.05°N, 159.45°E; summit elev. 1536 m
KVERT reported that moderate seismic activity from Karymsky continued to be detected during 31 May-8 June, and indicated that possible ash plumes rose to an altitude of 2.4 km (8,000 ft) a.s.l. on 31 May. Satellite imagery showed a thermal anomaly on the volcano during 3-4 and 6 June. The Aviation Color Code remained at Orange.
Geologic summary: Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetricalstratovolcano constructed within a 5-km-wide caldera that formed about 7,600-7,700 radiocarbon years ago. Construction of the Karymsky stratovolcano began about 2,000 years later. The latest eruptive period began about 500 years ago, following a 2,300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been Vulcanian or Vulcanian-Strombolian with moderate explosive activity and occasional lava flows from the summit crater. Most seismicity preceding Karymsky eruptions has originated beneath Akademia Nauk caldera, which is located immediately S of Karymsky volcano and erupted simultaneously with Karymsky in 1996.
KILAUEA, Hawaii (USA)
19.421°N, 155.287°W; summit elev. 1222 m
During 6-12 June HVO reported that the circulating lava lake periodically rose and fell in the deep pit within Kilauea's Halema'uma'u Crater, rising as high as the inner ledge about 60 m below the crater floor. Periodic measurements indicated that the gas plume from the vent continued to deposit variable amounts of ash and Pele's hair onto nearby areas. The lava pond in a small pit on the E edge of Pu'u 'O'o crater floor was visible with the web cameras. Lava flows periodically issued from vents on the S and south-central parts of Pu'u 'O'o's crater floor. Lava flows were active on the coastal plain and traveled as far as 1.6 km from the ocean. Lava flows were also sometimes active on the pali.
Geologic summary: Kilauea, one of five coalescing volcanoes that comprise the island of Hawaii, is one of the world's most active volcanoes. Eruptions at Kilauea originate primarily from the summit caldera or along one of the lengthy E and SW rift zones that extend from the caldera to the sea. About 90% of the surface of Kilauea is formed of lava flows less than about 1,100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 sq km, destroying nearly 200 houses and adding new coastline to the island.
19.023°N, 98.622°W; summit elev. 5426 m
CENAPRED reported that during 6-12 June gas-and-ash plumes from Popocatépetl rose above the crater, sometimes as high as 2 km, and drifted NNW, E, ESE, SSE, and S. Cloud cover occasionally prevented observations of the crater and plumes. Incandescence from the crater was visible on some nights. Incandescent fragments ejected from the crater fell onto the flanks on 8 and 11 June, and back into the crater on 10 June. The Alert Level remained at Yellow Phase Three.
Geologic summary: Popocatépetl, whose name is the Aztec word for smoking mountain, towers to 5,426 m 70 km SE of Mexico City and is North America's second-highest volcano. Frequent historical eruptions have been recorded since the beginning of the Spanish colonial era. A small eruption on 21 December 1994 ended five decades of quiescence. Since 1996 small lava domes have incrementally been constructed within the summit crater and destroyed by explosive eruptions. Intermittent small-to-moderate gas-and-ash eruptions have continued, occasionally producing ashfall in neighboring towns and villages.
31.585°N, 130.657°E; summit elev. 1117 m
JMA reported that during 4-8 June explosive eruptions from Sakura-jima's Showa Crater occurred 11 times and ejected tephra as far as 1.3 km from the crater. A small pyroclastic flow traveled 200 m down the E flank.
Based on information from JMA, the Tokyo VAAC reported that during 6-7 and 9-11 June explosions produced plumes that rose to altitudes of 1.2-3.7 km (4,000-12,000 ft) a.s.l. and drifted multiple directions. Pilots observedash plumes during 6-7 June that rose to altitudes of 1.8-3 km (6,000-10,000 ft) a.s.l. and drifted S, E, and NE. Explosions were detected on 8 and 12 June.
Geologic summary: Sakura-jima, one of Japan's most active volcanoes, is a post-caldera cone of the Aira calderaat the northern half of Kagoshima Bay. Eruption of the voluminous Ito pyroclastic flow was associated with the formation of the 17 x 23-km-wide Aira caldera about 22,000 years ago. The construction of Sakura-jima began about 13,000 years ago and built an island that was finally joined to the Osumi Peninsula during the major explosive and effusive eruption of 1914. Activity at the Kita-dake summit cone ended about 4,850 years ago, after which eruptions took place at Minami-dake. Frequent historical eruptions, recorded since the 8th century, have depositedash on Kagoshima, one of Kyushu's largest cities, located across Kagoshima Bay only 8 km from the summit. The largest historical eruption took place during 1471-76.
2.002°S, 78.341°W; summit elev. 5230 m
According to the Washington VAAC, a pilot observed an ash plume from Sangay on 6 June that rose to an altitude of 6.1 km (20,000 ft) a.s.l. and drifted N. Meteorological clouds prevented satellite image views. A pilot observed ash drifting E on 10 June.
Geologic summary: The isolated Sangay volcano, located E of the Andean crest, is the southernmost of Ecuador's volcanoes, and its most active. It has been in frequent eruption for the past several centuries. The steep-sided, 5,230-m-high glacier-covered volcano grew within horseshoe-shaped calderas of two previous edifices, which were destroyed by collapse to the E, producing large debris avalanches that reached the Amazonian lowlands. The modern edifice dates back to at least 14,000 years ago. Sangay towers above the tropical jungle on the E side; on the other sides flat plains of ash from the volcano have been sculpted by heavy rains into steep-walled canyons up to 600 m deep. The earliest report of an historical eruption was in 1628. More or less continuous eruptions were reported from 1728 until 1916, and again from 1934 to the present. The more or less constant eruptive activity has caused frequent changes to the morphology of the summit crater complex.
SANTA MARIA, Guatemala
14.756°N, 91.552°W; summit elev. 3772 m
Based on seismic data and visual observations, INSIVUMEH reported that on 6 June a lahar traveled down Santa María's Rio Nima I drainage. During 6-7 and 10-12 June explosions from Santiaguito lava-dome complex producedash plumes that rose 400-800 m above the crater and drifted SW. Lava flows produced block avalanches.
Geologic summary: Symmetrical, forest-covered Santa María volcano is one of a chain of large stratovolcanoesthat rises dramatically above the Pacific coastal plain of Guatemala. The stratovolcano has a sharp-topped, conical profile that is cut on the SW flank by a large, 1-km-wide crater, which formed during a catastrophic eruption in 1902 and extends from just below the summit to the lower flank. The renowned Plinian eruption of 1902 followed a long repose period and devastated much of SW Guatemala. The large dacitic Santiaguito lava-dome complex has been growing at the base of the 1902 crater since 1922. Compound dome growth at Santiaguito has occurred episodically from four westward-younging vents, accompanied by almost continuous minor explosions and periodic lava extrusion, larger explosions, pyroclastic flows, and lahars.
SHIVELUCH, Central Kamchatka (Russia)
56.653°N, 161.360°E; summit elev. 3283 m
KVERT reported that during 1-8 June explosive activity at Shiveluch continued. Ground-based observers and satellite imagery indicated that a viscous lava flow continued to effuse in the active crater, accompanied byfumarolic activity. Observers noted that ash plumes rose to an altitude of 8.5 km (28,000 ft) a.s.l. on 2 June. Satellite imagery showed a thermal anomaly over the lava dome during 31 May and 1-4 June, and ash plumes drifting 152 km S and 250 km S and ENE during 2-3 June. Seismic data indicated that possible ash plumes rose to an altitude of 8 km (26,200 ft) a.s.l. on 5 June. The Aviation Color Code remained at Orange.
Based on analyses of seismic data, the Tokyo VAAC reported that a possible eruption on 6 June produced an ashplume that rose to an altitude of 8.2 km (27,000 ft) a.s.l. Ash was not detected in satellite images.
Geologic summary: The high, isolated massif of Shiveluch volcano (also spelled Sheveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group and forms one of Kamchatka's largest and most active volcanoes. The currently active Molodoy Shiveluch lava-dome complex was constructed during the Holocene within a large breached caldera formed by collapse of the massive late-Pleistocene Strary Shiveluch volcano. At least 60 large eruptions of Shiveluch have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Frequent collapses of lava-dome complexes, most recently in 1964, have produced large debris avalanches whose deposits cover much of the floor of the breached caldera. Intermittent explosive eruptions began in the 1990s from a new lava dome that began growing in 1980. The largest historical eruptions from Shiveluch occurred in 1854 and 1964.
1.467°S, 78.442°W; summit elev. 5023 m
IG reported that during 6-12 June visual observations of Tungurahua were limited due to cloud cover. On 7 June lahars traveled SW down the Mapayacu drainage, carrying blocks 10-20 cm in diameter. Lahars also descended the Achupashal (NW) and El Confesionario (WSW) drainages, causing a temporary closure of the Baños-Penipe highway. On 10 June an explosion was detected by the seismic network; windows vibrated and ash fell in Manzano (8 km SW). An explosions was heard the next day, as well as sounds resembling rolling blocks. An ash plume rose 3 km above the crater and drifted W and E. Ashfall was reported in Manzano.
Geologic summary: The steep-sided Tungurahua stratovolcano towers more than 3 km above its northern base. It sits ~140 km S of Quito, Ecuador's capital city, and is one of Ecuador's most active volcanoes. Historical eruptions have all originated from the summit crater. They have been accompanied by strong explosions and sometimes bypyroclastic flows and lava flows that reached populated areas at the volcano's base. The last major eruption took place from 1916 to 1918, although minor activity continued until 1925. The latest eruption began in October 1999 and prompted temporary evacuation of the town of Baños on the N side of the volcano.
Source: Global Volcanism Program
Featured image: Mt. Bagana during an earlier eruption - image courtsey roamingadventures.com